How to save GeoTiff image

[Chris Cox]

You can't.

They didn't plan the GEOTIFF extensions very well at all. There is no way for Photoshop to know when to preserve, when to delete, and when to modify the GEOTIFF tags.

Also, it's Photoshop - no intercap.

[kara chan]

I have GeoTiff images and need to do some image processing(e.g. Auto Level) in Photoshop. When I simply use SAVE command under File from pull down menu, the Geotiff information in the header was lost and the image is no longer in GeoTiff format. It has changed to standard Tiff format. How can I maintain Geotiff information when I use PhotoShop to do the pre-processing of the image? please advice

thks & rgds,
Kara Chan

[kara chan]

I see
thank you

But do you know what is the mechanism when Photoshop Save an image? I am thinking when I open an image, Photoshop will generate a temp file in local directory and it will always use this file for further process. When I press Save button, Photoshop will convert this temp file to my orginal file name and that's why no GeoTiff information can be maintain after either Save or Save As command. pls correct me if I'm wrong

thks

[Chris Cox]

It's not that simple.

Photoshop reads the file into memory - there is no temp file as such.
Photoshop may page some of that out into the scratch files, but it still doesn't exist as a single file.

Once the image is in memory, the unknown tags are discarded.

So, when Photoshop goes to save the image, the tags are gone.

You can't really save an image "in place" in a file (which is what you seem to want) because of compression, different metadata sizes, etc.

[kara chan]

Chris

thanks for your information

kara